Hello friends, I’m new here…
Are we sure that the Collision “Group and Mask” pair works correctly in this editor?
Sometimes when I build, some objects don’t show up…
Sometimes when I build, collisions don’t work…
Sometimes when I build, everything works fine.
And all of this happens without making any changes! Just by pressing F5 
I did not experience such problem with groups and masks. Can you elaborate on the details? Maybe some screenshots from your game hierarchy and game when bugs happens? Possibly the code too?
Don’t get me wrong, but I actually deleted the project and the editor completely! It’s not normal to get different errors when you recompile a project that you haven’t made any changes to!
A small suggestion can make a big impact!
The “Group and Mask” section definitely needs to be looked at and edited first!
That’s interesting. Since you made no change, it should be an engine/OS error. Maybe if you specify your OS and version of Defold, the Defold team could help you with it better